During the year under review, the emphasis has been on methods for evaluating complex mixtures and for estimating chemical exposure and quantifying risks of chemical injury. Other activities included compiling monographs on chemicals selected for testing by the National Toxicology Program (NTP), evaluating exposure to and risks of ethylene dibromide (EDB), enumerating the hazards of sodium azide (the proposed inflator of air bags used as passive restraints in automobiles), and a compilation of all known work on thirty air pollutants regulated by the Environmental Protection Agency (EPA).